Processes are known for producing crystalline polyolefins by polymerizing alpha-olefins such as propylene and 1-butene in the presence of stereoregular catalysts. It is known that among these processes, processes for polymerizing alpha-olefins in the presence of a catalyst formed from (a) a highly active titanium solid catalyst component consisting essentially of magnesium, titanium, halogen and an electron donor, (b) an organometallic compound catalyst component and (c) an electron donor catalyst component give highly stereoregular polymers with high catalytic activity. These processes are employed on an industrial scale as excellent polymerization processes which do not require removal of the catalyst and an amorphous polymer from the polymers obtained after the polymerization. It has been desired in the art however to develop a better polymerization technique.
The present applicant proposed in Japanese Patent Publication No. 31726/1982 a process for polymerizing an alpha-olefin in the presence of a titanium catalyst component obtained by treating a complex of a magnesium halide compound and a titanium halide compound with an organic acid ester and a titanium compound, and an organometallic compound of a metal of Groups 1 to 3 of the periodic table.
Japanese Patent Publication No. 45403/1981 also proposed by the present applicant a process for polymerizing merizing an olefin in the presence of a catalyst composed of (A) a solid catalyst component obtained by reacting a titanium compound and an organic metal compound of a metal of Groups 1 to 3 of the periodic table in the presence of a complex of a magnesium halide compound and a titanium halide compound and (B) an organometallic compound of a metal of Groups 1 to 3 of the periodic table.
But a polymerization process which gives higher polymerization activity and stereoregularity than these processes has been sought.
It is an object of this invention to provide a process for polymerizing an alpha-olefin using a novel highly active catalyst.
Another object of this invention is to provide a process for polymerizing an alpha-olfein using a novel highly active catalyst of which activity is higher than in processes using conventional catalysts comprising (a) a highly active titanium solid catalyst component consisting essentially of magnesium, titanium, halogen and an electron donor, (b) an organometallic compound catalyst component and (c) an electron donor catalyst component and which can retain the excellent stereoregularity of the resulting polymer.
Further objects of this invention along with its advantages will become apparent from the following description.